Propeller



Julyll9, 1938. E. MARTIN 2,124,351

PRPELLER Filed .lune 28, 1935 ashets-sneet i E 42 58 i; y 40 ATTORNEY lJuy 19, 1938. t E, MARTIN 2,124,351

PROPELLER 3 Filed June 28, 1935 2 .Sheets-Sheet 2k IN V EN TOR.

A TTORNEY Patent-eci July 19, 1938 l Y PATENTy ori-lcs y, amsn Erle'`West jHartford, Conn., assigner to AUnited `Aircraft...-Cox'poiation,East Hartford,

. Conni., ya corporation of Delaware Application June y28, 41935, SerialNo. 28,888

' s claims. (ci. 11o-163') 'lhis invention relates to improyements inpropellers and has particular reference to a propeller in whic'li theblade is subject toangular adjustv A merit to produce anuoperatingcondition ofconstant engine sr'ied and is manually controllable so thatkthe'engin'e `speed maybe' variedat the will of the-operated.I

,-Anobjeot ofntiie` invention lies inthe provision ofan improvedanti-friction bearing between the (iV manual control, means and the.adjusting means.

...Other objects and advantages .will appear asV 1nthe anni' sum1drames@ I new@ inustrates' a 'suitable mechanical embodiment of'what isnowj considered to be the preferred form of n the invention. .'Thedrawings, howeverfare to 25 thereof. Fig. 2 is a cross sectional view onthel line 2--2 of Fig. l. Fig. 3 is a cross sectional view on the -line3-3 of Fig. l. Flg.4 is a plan view of a bearing member constructedaccording tothe idea of this invention.. Fig. 5 is a cross sectional .30view on the line 5-l of Fig. 4. Fig. 6 is a plan view of a bearingmember cooperating with the bearing member illustrated in Fig. 4. Fig. lis a cross sectional view on the line l-'l of Fig. 8. Fig. 8 is anelevational view of a retainer for the 35 anti-friction bail bearingscooperating with the bearing members illustrated in Figs. 4 and 8.

Fig. 9 is a plan view of the retainer and ball bearings illustrated inFig.,8, andFig. 10 is a cross sectional view on the line iii-ll of Fig.9.

Referring to the drawings in detail the numeral I0 indicates a. driveshaft of a motor such as an internal combustion engine. The drive shaftsupports and drives a propeller having blades, one

of which is indicated at i2, adjustably supported 45 upon the driveshaft by meansof a spider i! and a barrel il, asis clearly illustratedin Patent No. 2,032,255, of Frank- W. Caldwell. issued February 25,"1936. The patent referred to shows the propeller blade mounted upon aspider as indicated 50 at i5 for substantially frictionless rotationabout its axis and retained upon the spider against the ,action ofcentrifugal force by the' barrel member indicated at Il which isprovided with a flange 22 overlying a cooperating flange formed 55 uponthe root of the propeller blade.

'Ihe angle of thepropeller blades is adjusted in one direction by meansof centrifugally acting counterweights 24 and 25, one counterweightbeing attached to the root or base portion of each 'Y blade andoperating through the eect of centrifugal force upon rotation of thepropeller to increase the angle of the blade. to'which it is attached.As the two counterweights are exactly similar in all respects a detaileddescription of only one of them is considered suillcient for the purposeof this disclosure.4 The counterweight v2l comprises a member ofpreferably cylindrical or spherical shape attached to the root of theblade 20 by means of a counterweight bracket v2l in such a-manner thatthe counterweight is disposed in front of the propeller and is displacedina direction opposite to the direction of rotation of the propellerfromfaplane passing through the axis of the .drive shaft vi0 and theaxis 20 of the propeller blade i2. As the eil'ect of centrifugal forceupon a rotating object displaced from the axis of rotation tends toincrease the distance of the object from the axis of rotation,

it will be apparent that upon rotationof the propeller then will be atendency for the counter.

weight 24 to `move along a radial line passing through the center ofgravity of the counterweight and through the axis of the shaft I0. Thisradial line,- diverges from the radial line constituting the axis 20 ofthe propeller blade I2 inf/such a manner as to cause a force to be set.up substantially tangential to the circle of rotation of thecounterweight about the axis of the shaft i0 which'force acts to causethe counterweight to rotate about the axis 20 of the blade i2 inadirection opposite to the`direction that the blade tends to rotate or inthe direction of the arrow A on Figure 1. As the counterweight bracket2l is non-rotatably secured to the base or'root portion of the blade i2,this force in the direction of the arrow A will tend to increase theangle alpha between the longitudinal axis of the blade section and theplane of rotation of the major axis 2li of the blade; the angle alphabeing commonly referred to as the pitch or bladeV angle. While thecentrifugal force acting upon the counterweight 24 has a usefulcomponent in the direction of the arrow A operating to ad- Just theblade angle to maintain constant engine speed, it also has a componentin a radial direction which produces in the counterweight a turningmoment about an axis located inthe plane of the connection of thebracket member` 21 to the base of the propeller blade and disposed atright angles to the axis 20. The counterweight must The means foradjusting the blade angle of the' propeller.y blades I2 comprises acylindrical member slidably mounted upon a forward extension of theshaft I0 to move in opposite directions coincident with -the axis of thedrive shaft in response to changes in the pressure of fluid suppliedthereto by suitable hydraulic means controlled by the person operatingthe engine or by suitable automatic or speed responsive means. 'Ihiscylinder 30 is provided at its rearward end with a pair of radiallyextending arms, one of which is indicated at 32, and to these arms 32are secured tangentially extending pins as indicated at 34, theprojecting ends of which pass through arcuate cam slots 35 provided inthe counterweight bracketsA 21 so that upon the movement of the cylinder3D in the direction of the arrow B indicated in Figure 1 the pins 34sliding in the cam slots 35 will overcome the effect of the componentsof the centrifugal force acting on the counterweights 24 and 25 tendingto move the counterweights in a direction to increase the blade angle.of the propeller blades and will move the counterweights toward eachother in a direction to decrease the blade angle alpha of the propeller.While the connections comprising the arms 32 and pins 34 are effectiveto overcome the tangential component of the centrifugal force;

acting on the counterweights and move the counterweig'hts 24 and 25 to`adjust the blade angle of the propeller, it is among the objects of thisinvention to utilize this same connection to support the counterweightsagainst that radial component of centrifugal force which produces aturning moment about an axis perpendicular to y the axis 20 as describedabove.

The cam slot 35 extends through the counterweight bracket 21 from theside thereof adjacent to the arm 32 and for a distance sumcient toprovide the bearing 31 with sumcient strength to resist the centrifugalforce imposed upon the y counterweight and the free end of itsbracket-by reason of the rotation of the drive shaft lll, and is thenenlarged to receive a ball bearing generally indicated at 40. Y

This ball bearing comprises, an elongated ball race member 42,preferably made of hardened steel, seated upon the inner face of thebearing element 31 and provided with a slot 43 coincident with orparallel to the slot 35 and also provided Y in its exposed face with apair of grooves 44 and 45 of partly circular cross section arranged oneupon each side of the slot 43 and spaced therefrom preferably aboutone-half of the distance from the edge of the slot to the adjacent outeredge of the member 42 and extending for the entire length of theelongated member 42. The radially outer ,end of the pin 34 is providedwith an inverted cone shaped head 41 against which bears a circular ballrace '49 provided-with an aperture to receive the pin 34, said aperturebeing beveled as indicated at to receive the cone shaped head 41 of thepin. The surface of the Amember 49 opposite the bevel`50 is providedwith grooves 52 and 53 of partly circular cross section, as clearlyillustrated in Fig. 5, having a longitudinal curvature of the grooves 44and 45 respectively, provided in the outer surface of the member 42. Aplurality of bearing balls as indicated at 55 are disposed in thegrooves 44 and 45 of the member 42, some of these balls being at alltimes interposed between the members 42 and 49 to provide ananti-friction bearing for the sliding movements of the member 49 withrespect to the member 42. The balls 55 are mounted in a retaining cage53, preferably but not necessarily, formed of two pieces of sheet metalsecured together by suitable means such as spot welding or line weldingas indicated at 5l 'and provided with apertures 59 for receiving theballs, and tongues 50 partly surrounding the balls to retain them intheir respective apertures. The cage 58 is materially shorter than themember 42 being preferably one half the length of such bearing member sothat the pin 34 may traverse the entire length of the slot 35 before theend of the cage comes into contact with the adjacent end of the bearingreceiving opening provided in the counterweight support 21.

Ihe pin 34 is screw threaded into the arm 32 and for this purpose isprovided at its outer end with a slot 62 formed in an upstanding boss 53by means of which a suitable tool such as a screw driver may be appliedto the pin to thread it securely into a screw threaded aperture 55provided in the arms 32. Preferably the arm 32 is formed' of a.relatively light weight alloy such as an aluminum alloy and if desiredthe aperture 65 may be lined with a sleeve member 51 of hardenedmaterial provided at its outer end with a The ability of "the ballbearing to take laterall thrust provides for frlctionless movement ofthe counterweights about the axis 20 upon reciprocation of the cylinder30 and the ability of the ball bearing to take axial thrust provides forfrictionless movement of the pin 34 relative to the coun.- terweightbracket 21 while the pin is absorbing the thrust placed upon it by theradial component of the centrifugal force acting uponfthe respectiveccunterweights 24 or 25. 'I'he grooves 52 and 53 are providedwith'slightly rounded ends so that as the member 49 rides over the balls55, the balls will be directed intothe grooves and there will be notendency for the member to force the balls out of their position in thecage 58. The cylinder 30 carrying arms 32 is free to rotate about itsaxis but is held against rotation by the bearings 4U which exertdiametrically opposite balanced forces on the cylinder and areconstrained by thecounterweight brackets to move in dat arcuate paths.'I'hese forces place bending and tension loads on the' pins 34 whichmaintain the cylinder 30 against rotation. and cause the counterweightsto move relative to a plane passing through the axis of the shaft l0 andthe vairis 20 of the propeller blades as the cylinder 30 moves along theshaft I0 to alter the blade angle of the propeller `in response tomanual control.

While I have illustrated my invention as applied to a two bladedpropeller itis to be understood that it may be applied to propellershaving any desired number of blades. In all cases a separatecounterweight, counterweight bracket, cylinder arm, pin and bearing willbe provided for each bladeof the propeller.

From the above description, it will be observed that I have provided ina propeller, subject to controllable adjustment, anti-friction bearingmeans between the controlling means and the adjusting alegan trollingmeans against that component of centrifugal force acting upon theadjusting means which tends to carry the centrifugally acting adjustingmeans away from their operative association with the propeller blades.

While I have illustrated and described a parfl ticular 'mechanicalembodiment which my invention may take, it is to be understood that theinvention is not limited to the specic embodiment so illustrated anddescribed, but that such changes in the size, shape and arrangementofparts may be resorted to as come within the scope of the appendedclaims.

Having now disclosed my invention so that others skilled in the art mayclearly understand the same, what I desire to secure by Letters Patentis as follows:

1. In a controllable propeller having jblades journalled for angularadjustment about their axes, adjusting means secured to each blade andmovable therewith for increasing the blade angle, and power actuatedcontrol means for controlling the action of said adjusting means, anantifriction connection between said adjusting means and said controlmeans comprising, flat 'race members slidable longitudinally withrespect to each other and secured to said adjusting means and saidcontrol means respectively, and a group of anti-friction elementsdisposed between said race members and extending beyond one of saidrace4 members in the direction of relative movementv therebetween.

2. In a controllable propeller having 'blades journalled for angularadjustment about their axes, adjusting means secured to eachblade andmovable therewith for increasing the blade angle, and control means' forcontrolling the action of said adjusting means, an anti-frictionconnection between said adjusting means and said control meanscomprising, an elongated fiat race membercarried by said adjustingmeans, atension pin carried by said control means extending through aportion of said adjusting means and said elongated race carried thereby,a flat lrace member carried by said pin and movable relative to the racecarried by said adjusting means in the direction of the length thereof,and anti-friction elements disposed between said race members to roll inthe direction of relative movement therebetween;` A f 3. In. acontrollable propeller having blades journalIed'for angular adjustmentabout their axes, means secured to each blade and movable therewith foradjusting the blade angle, and control means for controlling. the actionof said `adjusting means, an anti-friction connection between saidadjusting means and said' control means comprising, an elongated flatrace member carried by said adjusting means, a pin carried by saidcontrol means and extending through elongated slots provided in saidadjusting means l and in the race member carried thereby, ,asubstantially circular race member carried by said pin to react withsaid first mentioned race mem'- ber and movable relative thereto in thedirection of the length thereof, a pair of grooves in said race membercarried by said adjusting means disposed `o ne upon each side of theslot provided in -said race member and extending the length of said racemember, a pair of corresponding' 4. In a controllable propeller havingblades journalled for angular adjustment about their axes, means securedto.eachy blade and movable. therewith for adjustingthe blade angle, andcontrol means for controlling the action of said adjusting means, ananti-friction connection between said adjusting means and said controlmeans comprising, an elongated 'iiat race member carried by saidadjusting means, a pin carried by said control means and extendingthrough slots provided in said adjusting means and said race member, asubstantially circular race member carried by said pin and movable withrespect to the race member carried by said adjusting means in theAdirection of the length thereof, corresponding grooves in said racemembers extending for the length thereof in the direction of relativemovement, anti-friction balls disposed in said grooves to roll thereinand a retainer for said balls comprising, a fiat plate having ballreceiving apertures therein and means for retaining said balls in saidapertures.

5. In a propeller having blades journalled for friction connectionbetween said control meansand said centrifugal means comprising, anelongated ball race supported upon the bottom of said depression andprovided with an aperture therethrough coextensive with said cam slot,an

arm on said control means, a pin fixed in said arm and extendinglthrough said cam slot and said elongated ball race carried by the freeen d of said pin and movable with respect to said elongated ball race ina direction along the length of said cam slot, cooperating grooves insaid ball races upon opposite sides of said cam slot, and a plurality ofanti-friction balls in said grooves.

6. In a propeller having blades journalled for angular adjustment abouttheir axes and having centrifugalv means to increase the angle of saidblades and power actuated control means for opposing the action of saidcentrifugal means in which each centrifugal means4 is provided with anenlarged elongated depression therein and an elongated cam slotextending through the bottom of said depression, means providing an4antifriction connectionlbetween said control means and said centrifugalmeans comprising, an elongated ball race supported upon the bottom ofsaid depression and provided with an aperture therethrough coextensivewith said cam slot, an arm on saidcontrol means, a pin fixed in said armfand extending through said cam slot and said elongated ball race intosaid depression, a substantially circular ball race carried by the freeend of said pin and movable with respect to said elongated ball race ina direction along the journalled for rot'ative adjustment about theiraxes, a counterweight fixed to each blade for rotating said blade in adirection to increase the blade angle, a hydraulic cylinder movable inopposite directions to control the blade angle of said propeller inopposition to said counterweights,A and means connecting said cylinderwith sald counterweights said means comprising, arms on said cylinderspaced around the circumference thereof in accordance with the angulardistance between the blades of said propeller, a pin on each armextending through a cam slot provided in the associated counterweight,an elongated iat bearing carried by each counterweight, a bearingcarried on the `free end of each pin overlying the elongated bearingcarried-by the respective counterweight, and antifrction elementsbetween said superimposed bearings.

8. In a controllable pitch propeller having blades journaled for angularadjustment about their axes, adjusting meansl secured to each blade andmovable therewith for increasing the blade angle, and control means forcontrolling the action of said adjusting means, an anti-frictionconnection between said adjusting means and said control meanscomprising, an elongated v Amembers to roll in the direction of relativemovement therebetween.

